1. Technical Field
This invention relates to materials for absorbent articles, such as disposable diapers, incontinent briefs, and feminine pads. More particularly, this invention relates to the localized use of fine denier fibers, such as meltblown fibers of very low denier, in conjunction with a spunbonded web to maximize hydrophobicity of selected regions of disposable absorbent articles such as diapers, briefs and pads.
The present invention has further relation to the application of a meltblown fiber-spunbonded web combination in the standing cuff region of disposable absorbent articles.
2. Discussion
It has long been known in the art of disposable absorbent articles that it is extremely desirable to construct absorptive devices, such as disposable diapers, incontinent briefs, sanitary pads, and the like, so that leakage of body fluids is prevented. Disposable diapers, incontinent briefs, and sanitary pads are well known articles of manufacture which are respectively worn by infants, incontinent adults, and menstruating women. Diapers and briefs are worn about the lower torso and are intended to absorb and contain urine and feces thereby preventing the urine and feces from soiling, wetting, or otherwise contaminating articles (e.g., clothing and bedding) which come into contact with the wearer. Sanitary pads serve a similar protective function.
In general, disposable absorbent articles all have the same basic structure which comprises an absorbent core encased between a liquid permeable user contacting topsheet and a liquid impermeable backsheet. The prior art, of course, teaches numerous variations of and elements in addition to the basic topsheet, backsheet, and absorbent core arrangement. Many of these improvements are directed to overcoming the problem of side leakage along the thigh of the user. For example, and with particular respect to diapers and briefs, an improvement in the performance of these articles has been achieved by the addition of elastic along the portion of the disposable article which contacts the wearer's thigh thereby providing elasticized leg openings when the article is worn. Exemplary of this improvement is U.S. Pat. No. 3,860,003 issued on Jan. 14, 1975 to Buell for CONTRACTIBLE SIDE PORTIONS FOR DISPOSABLE DIAPER and commonly assigned to the assignee of the instant application.
Experience has taught that while elasticized leg openings improved the control of side leaks, additional barrier protection was necessary. Leg "cuffs" were developed in response to this need. The traditional cuff comprises a strip of fluid-impermeable material that is attached to the body of the article by stitching or by adhesive. When the absorbent article is lying flat or when in its folded state as provided to the consumer, the cuffs generally lie flat adjacent the topsheet. When worn, the cuffs extend perpendicularly with respect to the topsheet to nest in the groins of the wearer from front side to back side, thus wrapping around the crotch area and forming a fluid-impermeable seal. Instead of leaking out of the absorbent article and along the wearer's thigh, body fluid is supposed to be retained within the confines of the area formed between the generally parallel fluid-impermeable cuffs and the fluid-impermeable backsheet.
While some of the problems of providing leakage resistant waste containment garments have been at least partially ameliorated by previously-disclosed garments, none has solved the problems in the manner or to the extent of the present invention. Specifically, there is known in absorbent articles of the prior art a tendency for flowing, non-absorbed liquids to pass under the attachment seam formed where the cuff is hinged to the body of the absorbent article.
In addition to known cuffs allowing leakage, these cuffs are typically composed of materials that are either insufficiently hydrophobic, are resistant to the passage of air and hence do not "breathe" (typical of conventional nonwoven laminates) or are too costly to be used in mass production. Furthermore, certain types of known cuffs are not composed of material which is particularly soft to the touch, thus making the cuffed article unpleasant to wear.
It is clear that known disposable absorbent articles have generally failed to overcome the problem of side leakage.
It is therefore an object of the present invention to overcome the disadvantages associated with known absorbent articles by providing a disposable absorbent article that effectively resists the passage of body fluids beyond its confines.
It is a further object of the present invention to provide a cuff assembly that is composed of at least two nonwoven layers of material to provide maximum hydrophobicity.
Still another object of the present invention is to combine meltblown and spunbonded polymers to provide ranges of hydrophobicity in a cost optimized manner to meet the specific physical property needs as required for different regions across the width of the cuff assembly.
Still a further object is to provide cuff assemblies composed of combined spunbonded and meltblown fibers demonstrating superior hydrophobicity to conventional spunbonded or carded materials of similar weights.
Another object of the present invention is to provide cuff assemblies that demonstrate superior resistance to loss of hydrostatic head due to manipulation as compared with conventional spunbonded or carded materials or non-optimized multidenier materials.
Yet a further object of the present invention is to provide cuff assemblies that allow for the transmission of air while retaining hydrophobic properties. This "breathable" characteristic makes articles constructed according to the following design more comfortable to wear.